1. Field of the Invention
The invention pertains to the field of exhaust systems. More particularly, the invention pertains to an exhaust system with air purging.
2. Description of Related Art
Doser valves are used to inject fuel into the exhaust system of diesel engines to burn particulate matter in a filter and thus clean them out. Therefore, they are mounted on the “hot” side of the engine in the exhaust system. Due to the very high temperatures within the exhaust system on the “hot” side of the engine, the PWM operating mode, and the necessary valve seat materials used, minute leakage of the doser valve occurs. This leakage may promote fuel to coke and clog the spray orifice of the doser valve compromising specific spray patterns, decreasing the efficiency of the filter cleaning process and of the engine.